The present disclosure relates to video coding and, in particular, to coding techniques that find application in resource-limited devices.
Video processing and rendering systems are deployed in an ever-widening array of consumer electronic devices. Initially, such systems were the province of dedicated processing equipment but, over time, such systems found application in personal computing environments, tablet computing and smartphone environments and, more recently, smart watch environments. Smart watches tend to have less computational resources than smartphones and smartphones tend to have less computational resources than personal computers. While modern video coding protocols may employ processing techniques that are appropriate for one type of processing device (say, a personal computer or smartphone) these same techniques may be too complex for another type of processing device (say, a smart watch).
Similarly, display characteristics may vary widely from device to device. A personal computer or tablet computer may utilize displays that are far larger than their smart watch counterparts. A coded video stream that has sufficient image content to drive a display on a tablet computer may have far too much data to drive a display on a smaller smart watch. Image content may have to be rescaled to be displayed on the smart watch. However, the smaller display size of a smart watch may cause viewers to zoom in and out of displayable video, and, as a consequence, image data that would not be displayed if an entire field of view of image data were shown may be required at a moment's notice in response to a zoom event. Additionally, smart watches and other devices may receive coded video over bandwidth-constrained communication links, which further constrain the devices' capacity to receive and decode coded video.
Accordingly, the inventors have identified a need in the art for a coding system that codes video data in a manner that uses communication bandwidth effectively and responds quickly to zoom events at a destination device that may communicate with the coding system notwithstanding communication latencies between the coding system and its display device.